In the course of surgical correction of several forms of congenital heart disease, the pulmonary valve may be rendered regurgitant. Over the long term this is very well tolerated. In the acute postoperative period, however, right ventricular failure is a significant and potentially life threatening complication. While the cause of RV failure may be multifactorial, the extra work produced by the pulmonary regurgitation may worsen the RV failure. This study evaluated in laboratory animals the use of a balloon device to occlude the pulmonary artery during diastole and thus prevent pulmonary regurgitation. The balloon is connected to the control panel for an intra-aortic balloon pump to control the inflation and deflation of the balloon. In 8 sheep the pulmonary valve was completely excised. This resulted in pulmonary regurgitation which was compensated by increased stroke volume and greatly increased RV stroke work. Use of the pulmonary artery balloon, functioning as a "valve", completely prevented regurgitation and reduced RV work.